With the rapid development of a Software Defined Network (SDN) technology and Network Function Virtualization (NFV) in these years, network deployment is becoming more controllable, and control complexity is also getting higher and higher. In particular, control means for intermediate networks such as core networks and convergence networks are more and more complicated in order to adapt to different services and meet different deployment requirements. In particular, the number of intermediate network node states required for multicast applications such as a Multicast Virtual Private Network (MVPN) and an Internet Protocol Television (IPTV) is increased exponentially.
To this end, the industry has proposed a new technology for constructing multicast forwarding paths, called a Bit Indexed Explicit Replication (BIER) technology. The BIER technology can greatly reduce the protocol complexity and intermediate state of an intermediate network by completely transforming a forwarding layer. The network forwarding is simplified to be based only on bits, subverts the traditional Internet Protocol (IP) forwarding, can easily realize the transmission of multicast traffic in the intermediate network without recording, by the intermediate network, any multicast traffic status, and greatly facilitates network operation and maintenance.
BIER is a bit-based multicast replication technology. In a BIER domain, each Bit-Forwarding Egress Router (BFER) is assigned with a globally unique bit position in the entire BIER sub-domain. Each BFER floods the BIER domain with its own bit position using an Interior Gateway Protocol (IGP). All bit positions form a bitstring, and the transfer and routing of a data packet in the BIER domain depends on the bitstring. When a packet header containing the BIER is received by other Bit Forwarding Routers (BFR), the packet header is forwarded according to the bitstring carried in the BIER header based on a bit forwarding table. This principle of forwarding based on a BIER bit greatly reduces the forwarding cost of a network.
Bit Index Explicit Replication-Traffic Engineering (BIER-TE) is similar to BIER. It forwards and replicates packets according to BitString in the packet header, but the key differences of BIER-TE and BIER are as follows:
1) An explicit path calculated using a BIER-TE controller replaces automatic path calculation within a network.
2) Each bit position in a BitString represents one or more adjacencies, not a BFER.
3) Only a BIER-TE Forwarding Table (BIFT) is required on the BFR, and no routing table is required.
At present, the way to protect a path in BIER-TE in the related art is mainly for explicitly creating a unique backup path for a certain path. This solution may cause that the path only exists in a Fast Re-Route (FRR) entry. However, when a link belongs to multiple FRR entries, the correct and reasonable configuration path protection cannot be implemented, resulting in waste of resources.